Rail system

ABSTRACT

A rail system comprising an elongate ducting trough ( 22 ) located, for example, generally centrally along a swept path ( 20 ). The ducting trough ( 22 ) comprises a plurality of trough sections, each defining a pair of channels ( 24, 26 ) for housing electrical cables (not shown). The system further comprises a pair of rails ( 34 ) positioned, for example, on either side of the ducting trough ( 22 ) and running substantially parallel thereto. The rails ( 34 ) and the ducting trough ( 22 ) are substantially in the same plane and/or at substantially the same level.

This invention relates to a rail system and, more particularly, a methodand apparatus for providing a rail system, such as (but not exclusive) astreet-running tram or light rail system.

FIG. 1 shows the prior art. Traditionally, in order to provide atrackform for rails 34, it is necessary to excavate street 10 (betweenfootpaths 12 having kerb 14) to provide an envelope to contain the substructure for the trackform and the required High and Low voltage ductbanks (often referred to as conduits). The width of this envelope is afunction of the width of the rail vehicle whilst moving (DevelopedKinematic Envelope), the track geometry (vertical, horizontal and cant)and the High and Low voltage duct bank configurations. The excavationdepth is typically around 1200 mm to 1500 mm (vertically) below existingroad level.

At around the above-mentioned depth (typically 1200 mm to 1500 mm belowexisting road level) the High and Low voltage duct banks, 24, 26 areprovided, typically either side and outside the trackform. Historically,these duct banks are at greater vertical depth than the rails 34 andwould come no closer than 600 mm (vertically) to the finished top ofrail level. The High and Low voltage duct banks 24, 26 are required toensure the rail system can operate.

A suitable sub-grade material 20 (to comply with Highways agency orlocal government specifications for example) is then placed between theducts 24, 26 if required and a flush surface is provided typicallyaround 500-600 mm below the finished top of rail level.

In accordance with a first aspect of the present invention, there isprovided a rail system, comprising an elongate ducting trough locatedalong a swept path, said ducting trough being for housing electricalcables, and at least one rail on which a train or tram runs, said railbeing positioned alongside and generally parallel to said ductingtrough.

Also in accordance with the first aspect of the present invention, thereis provided a method of providing a rail system, comprising the steps ofproviding an elongate ducting trough along a swept path, said ductingtrough being for housing electrical cables, and providing at least onerail alongside and generally parallel to said ducting trough.

Beneficially, the ducting trough and the at least one rail are insubstantially the same plane and/or at substantially the same level, inuse.

The ducting trough may, for example, be positioned substantiallycentrally (with one or more rails being positioned to the side thereof)or it may be positioned at or adjacent the side of the swept path.

In accordance with a second aspect of the present invention, there isprovided a trough section for use in constructing a rail system, saidtrough section defining at least one channel for housing electricalcables and being adapted to be positioned generally centrally within aswept path alongside and generally parallel to said at least one rail.

Preferably, the trough section has a built-in radius at one or more endssuch that two or more trough sections may be positioned adjacent to eachother and fit snugly together, even if they are being placed around acurve or bend. The or each trough preferably defines at least twochannels, one for housing low voltage cables and the other for housinghigh voltage cables.

The swept path of the rail system can be relatively shallow, say around500 mm, or so, such that the number of utilities affected by theexcavation can be minimised, if not eliminated altogether. Means, suchas a cantilevered structure, may be provided to carry a feeder pole,such that the need for deep excavation for this purpose is alsoeliminated.

The ducting trough, or each trough section, is beneficially formed ofreinforced concrete. Some sections may comprise unitary structures,whereas one or more others may be provided with an opening at the tophaving a removable cover, thereby to allow access to the electricalcables housed within the channels. In one embodiment of the presentinvention, a trough having a removable cover is placed at spaced-apartintervals (say every 100m or so) along the length of the rail system.

An exemplary embodiment of the present invention provides a simplifiedconstruction method by providing conduits at a high level, which alsoprovide temporary lateral support to the rails during the constructionprocess.

According to another aspect of this invention, there is provided a railsystem comprising a ducting trough or support member and at least onerail; the rail being positioned along side the ducting trough or supportmember.

Preferably the rail and ducting trough or support member are positionedat substantially the same depth. Beneficially, the rail and the ductingtrough or support member are of substantially the same height and/or insubstantially the same plane, in use.

Also according to this invention there is provided a trough or supportsection for use in constructing a rail system, the trough or supportsection having either securing means (or allowing securing means to beattached to it) or defining at least one channel for housing electricaland mechanical cables and equipment and being adapted to be positionedgenerally along side at least one rail.

Preferably the securing means is a thread, although this is notessential.

It is also preferable that the trough or support section has built inradii at one or more ends such that two or more trough sections may bepositioned adjacent to each other and fit snugly together in both thehorizontal and vertical planes. (This depends on the constructionmethod, the above is more relevant to pre-cast or “off-site”manufacture, however, cast “in-situ” solutions are equally applicable).

More preferably the trough or support section defines at least twochannels, one for housing low voltage cables and the other for housinghigh voltage cables.

Even more preferably the trough or support section is at least partiallyformed of reinforced concrete, composites, resin, or polymer. And it maycomprise a substantially unitary structure or a substantially solidstructure.

Preferably the trough or support section includes electrical cableshoused within the channels.

Preferably the trough or support section comprises at least one barextending outward from the section.

Preferably the rail system has a ducting trough or support membercomprising one or more trough or support sections.

Preferably the rail system comprises a depth of construction which isrelatively shallow.

Preferably the rail system includes means for carrying electrical ormechanical equipment.

One means of carrying electrical and mechanical equipment is acantilever structure.

Preferably the rail system has ducting trough or support membercomprising a combination of trough or support sections.

Preferably the rail system has ducting trough or support member havingone or more removable covers.

More preferably the rail system has one or more removable covers whichare spaced apart at intervals along the length of the ducting trough orsupport member.

Also according to the invention there is provided a method ofconstructing a rail system, comprising the steps or providing anelongated ducting trough or support member substantially positionedalong side at least one rail.

Preferably the method of constructing a rail system comprises the stepsof laying an elongated ducting trough or support member, then laying asub-base, positioning at least one rail substantially along side theducting trough and then pouring a concrete slab.

More preferably the at least one rail and ducting trough or supportmember are positioned at substantially the same depth. Beneficially, therail and the ducting trough or support member are of substantially thesame height and/or in substantially the same plane, in use.

Preferably the method of constructing a rail system comprises theadditional step of securing a gauge support frame to the ducting troughin order to position at least one rail.

These and other aspects of the present invention will be apparent from,and elucidated with reference to the embodiment described herein.

An embodiment of the present invention will now be described by way ofexample only, and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a rail system according tothe prior art;

FIGS. 2A-2F are schematic cross-sectional views of the various stagesinvolved in providing a rail system according to an exemplary embodimentof the present invention;

FIG. 3 is a schematic plan view of a rail system according to anexemplary embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a rail system according toan exemplary embodiment of the present invention;

FIG. 5 is a perspective view of a trough section according to anexemplary embodiment of the present invention;

FIG. 6 is a side view of the trough section of FIG. 5;

FIG. 7 is a side view of an alternative trough section;

FIG. 8 is a schematic cross-sectional view of the trough of FIG. 5;

FIG. 9 is schematic plan view of a plurality of trough sections fittedtogether along a bend;

FIG. 10 is a schematic cross-sectional view of the trough section ofFIG. 5, illustrating the reinforcement features thereof;

FIG. 11 is a schematic cross-sectional view of a rail system accordingto an exemplary embodiment of the present invention;

FIG. 12 is a schematic side view of a stray current isolation joint;

FIG. 13 is a perspective view of part of a drainage box for use in thesystem of FIG. 11;

FIG. 14 is a schematic cross-sectional view of a rail system accordingto an exemplary embodiment of the invention, illustrating a troughsection having a removable cover;

FIG. 14A is a schematic perspective view illustrating the cover of thetrough section of FIG. 14;

FIG. 15 is a schematic plan view of the rail system of FIG. 14;

FIG. 16 is a schematic perspective view illustrating the cantileveredstructure of a feeder pole base, provided off the track of a rail systemaccording to an exemplary embodiment of the present invention; and

FIG. 17 is a schematic cross-sectional view of a rail system accordingto an exemplary embodiment of the invention, illustrating the connectionof the high voltage cables to a feeder pole.

Referring to FIGS. 2A to 2I inclusive of the drawings, an overview of apreferred method of constructing a rail system according to an exemplaryembodiment of the invention will now be given.

The trackform design is based on a single poured Continuously ReinforcedConcrete Pavement (CRCP) design conforming with the Highways AgencyDesign Manual for Roads and Bridges (DMRB). However, other trackformconstruction methods can equally be used, for example, Jointed ConcretePavements (JCP), Continuously Reinforced Concrete Roads (CRCR),un-reinforced trackforms, concrete bearers cast into a trackform, glassfibre (or other fibre) reinforced, or ballasted track.

As shown in FIG. 2A, a typical street comprises a road section 10 andfootpaths 12 running either side of the road section 10. Each footpath12 is generally defined by a kerb 14. Drainage gulleys 16 are providedat the interface between the road section 10 and the kerb 14. Thedrainage gulleys 16 normally connect into respective carrier drains 18running longitudinally with the street.

With reference to FIG. 2B, the first step of the method would generallyinvolve excavating a section of the road 10. This excavation depth wouldtypically be 500 mm deep and uniform across the width of the trackformonly. The width is a function of the type of rail vehicle, trackgeometry and other constraints depending upon uniquenesses of theparticular location. However, for the “plain line” case, 500 mm is atypical figure.

The 500 mm depth would be “saw cut” vertically into the existing highwaysurface and material to this depth is excavated between the vertical“saw cuts”.

It will be appreciated that historically, in order to provide sufficientformation stiffness, the Californian Bearing Ratio (CBR) percentage, asoutlined in the Highways Agency DMRB publications of 15% or highershould be attained. If CBR of 15% or higher is not attained, thencapping layers shall be provided complying with the DMRB as describedabove.

If CBR's of 15% or higher are attained the bottom of formation will becompacted with suitable construction plant.

It should be noted that this invention does not rely on CBR of 15% beingachieved; CBR's can be lower, say minimum 5% due to the load pathcreated by a concrete trackform, or other trackforms outlined earlier.

Once the material has been excavated, a ducting trough 22 is positionedalong the centreline of the excavation, see FIG. 2C. It should be notedhowever, that the ducting trough 22 may also be placed to either side ofthe excavation.

The structure, formation and features of the ducting trough 22 will bedescribed in more detail below. However, it will be noted, that for thisexample, the ducting trough 22 defines two parallel channels 24, 26, onefor the Low voltage cables and the other for the High voltage cables.Other cables can also be carried by these apertures.

Referring to FIG. 2D of the drawings, the next step of the processinvolves the placing of a layer of sub base material 27 (of say 150 mmdepth, fitting flush up to the “saw cut” highway on one side and thetrough 22 on the other). This material will comply with the DMRBrequirements, and will normally be a Cement Treated Basecourse. Thismaterial will be well compacted. Other material types may be used.

As illustrated in FIG. 2E, a first layer (the bottom layer) of steelreinforcing mesh 28 is placed on top of the sub base material 27, andwelded as required for stray current collection purposes.

The rail 34 is then placed in the excavation and welded to form acontinuous length to suit the site conditions. Alternatively, twochannels can be formed by formwork. The channels are dimensioned to takea rail of desired section. The rail can be placed into these channels ata later time.

A top trackform reinforcement, preferably a mesh 32, rail supportreinforcement 30 and any other ducting requirements for signalling,stray current collection, drainage products and pipes etc. is put inplace.

Referring to FIG. 2F of the drawings, each pair of rails 34, forming atrack is supported in this example by the “top down” rail constructionmethod by using Gauge Support Frames (GSF's) 36 which are stabilisedlaterally by fixing the GSF to a thread (see FIG. 8) cast into thetroughs 22 at nominal centres (say every 500 mm for maximumflexibility).

All of the mesh 28, 30, 32 is welded together and is also used as theprimary stray current collection system. At this time the mesh is spaced28, 30, 32 as required, to provide reinforcement cover. It will beappreciated that the rails (or formed channels for the rails) will bechecked for line and level at this time.

As can be seen, the GSF's 36 each have a pair of prongs 40 which extendinto the and co-operate with the mesh layers, whilst the rails aresuspended by the GSF's. As previously mentioned all products, ducting,drainage 3tc. will be set to position at this time, prior to pouring thetrackform concrete.

This construction method (i.e. GSF) is state of the art, but aconventional process for trackwork specialists, and will therefore notbe described in any more detail.

The drainage boxes 31 will be linked to the existing drainage systemprovided by the drainage gulleys 16 and associated carrier drains 18 (asillustrated in FIG. 4).

Referring to FIG. 2G, structural concrete is then poured into theexcavation up to a level 35-100 mm say below the final top of raillevel, for this particular example. When the concrete has reached arequired strength, usually after two to three days, the GSF's areremoved and the holes left by the GSF legs 40 are filled with a nonshrink grout or similar material.

Concrete shoulders 44 can then be cast level with the top of the rails.These are not essential, and could be replaced by a full width concretefinish, Pre-Cast Modular Block finish, or a bituminous surface laidadjacent to the rail.

It is often advisable to expose the aggregate contained within theconcrete to attain as high a skid resistance value as is possible. It isfurther advisable to colour the concrete to match aesthetically thesurrounding road surface, or alternatively make the rails “stand out”.

PSV values must satisfy the requirements stipulated by the DMRB and duecare and attention must be given to ensure that the PSV of the differentmaterials is as close to each other as possible, thus mitigatingpossible highway vehicle differential skid resistance issues.

Finally, highway “tie in” details are constructed. The reader shall notethat the trackform/highway interface was “saw cut”, the highway “tie-in”details shall be kept as simple as possible, while also satisfying therequirements of the DMRB. See FIG. 2I and FIG. 4 showing an example ofthis detail.

The finished rail system can be seen in more detail in FIGS. 3, 4, 14,15 and 17 of the drawings.

In the second embodiment of the invention ducting trough 22 need notprovide housing of the electrical cables but utilised for constructionpurposes. In this embodiment the trough 22 may be a support memberproviding formwork or support for the GSF's as described above.

Referring to FIGS. 5 to 10 of the drawings, the ducting trough 22 willnow be described in more detail. As shown, an exemplary embodiment ofthe ducting trough 22 according to the invention is made up of aplurality of ducting sections 50, each defining channels 24, 26 runningtherethrough. Each section 50 has a built-in radius at opposing endsthereof, for example, as illustrated in FIG. 6 or alternatively FIG. 7,such that the sections fit together snugly, even around bends (in boththe horizontal and vertical planes), and can, therefore, be articulatedas illustrated in FIG. 9.

Each trough section 50 is made of concrete, reinforced by steel mesh 52as shown in FIG. 10. Metal bars 54 may be embedded in, and extendoutward of, each section 50. Bars 54 can be used as fixities forconvenient lifting or craning of each section 50 into position. A pairof threads 56, as shown in FIG. 8, may be cast into the top of eachsection 50 for use in stabilising the gauge support frame (as explainedabove). It will be appreciated that the configuration of each troughsection 50 according to this exemplary embodiment of the inventionprovides no water paths or construction joints, such that it acts as aFaraday cage to prevent, or at least minimise, stray current.

Referring to FIGS. 14, 14A and 15, at spaced-apart intervals (say every100 m) the trough section 50 having a removable cover 60 (or “manhole”)may be provided to enable convenient placing of, sight of and access tothe cables in the channels 24, 26. In addition, this provides, forexample, a convenient way for maintenance workers to measure straycurrent at specific points along the track. The cover 60 may comprise areinforced concrete slab housed within a steel tray 62 which is boltedon the top of the trough section 50. The cover may be removably held inplace by a number of anti-vandal bolts 64.

Referring now to FIGS. 16 and 17, the high voltage cables housed inchannels 26 of the ducting trough 22 are connected to feeder poles 70for carrying current back to the sub-station. The feeder poles 70 areprovided at spaced apart intervals along the train line. A cantileveredstructure 72 provided to the side of the track may be provided to carryeach feeder pole 70. This eliminates the need for deep excavation forthis purpose.

Referring to FIG. 3F, each pair of rails 34 is supported top down by agauge support frame (GSF) 36 which is stabilised by a respective threadcast into the top of the trough 22. A pair of GSF's 36 are provided atspaced apart intervals along the length of track path. All of the meshis then welded together and spaced as required. It will be appreciatedthat the position of the rails 34 may be needed to be checked at thisstage before they are permanently fixed. As can be seen, the GSF's 36each have a pair of prongs 40 which extend into and co-operate with themesh layers 28,32, while the rails 34 are suspended above the bottom ofthe draining boxes 30 by the bracket-like members 42 at each end of theGSF 36. This is a conventional process and will not be described in anymore detail.

Thus the present invention relates to a design and construction methodfor providing a trackform encompassing a holistic design and associatedconstruction method, taking into consideration ease of construction,operation, maintenance and demolition.

The design and associated construction method, is a fully integratedmulti-disciplinary engineering solution concerning, civil, rail,electrical and mechanical and signalling resulting in a safe, easilymaintainable operational rail system.

The rail system example given here within rates to a street running (orflush paved) trackform. This is just one embodiment of the proposed railsystem, and to the experienced reader skilled in the art of engineering,adaptions on this theme will become immediately evident.

The rail system is however equally applicable to all other forms of raildesign and construction. These include without excluding others;segregated running, tram, metro, light rail, heavy rail, high-speed railand freight rail system. This rail system can be applied to all aspectsof rail design and construction; for example, at grade, within a tunnel,running with a highway or elevated etc.

All technical phrases referred to are well known in the United KingdomRail Industry, e.g. Her Majesty's Railway Inspectorate Railway SafetyPrinciples & Guidance documentation.

An embodiment of the present invention has been described above by wayof example only, and it will be appreciated by a person skilled in theart that modifications and variations may be made to the describedembodiments without departing from the scope of the invention as definedby the appended claims.

1. A rail system comprising an elongate ducting trough located along aswept path, said ducting trough being for housing electrical cables, thesystem further comprising at least one rail on which a train or tramruns, said rail being positioned alongside and generally parallel tosaid ducting trough.
 2. A rail system according to claim 1, wherein saidducting trough and said at least one rail are in substantially the sameplane and/or at substantially the same level, in use.
 3. A troughsection for use in constructing a rail system according to claim 1, saidtrough section defining at least one channel for housing electricalcables and being adapted to be positioned within a swept path, alongsideand generally parallel to said at least one rail.
 4. A trough sectionaccording to claim 3, having a built-in radius at one or more ends suchthat two or more trough sections may be positioned adjacent to eachother and fit snugly together.
 5. A trough section according to claim 3,which defines at least two channels, one for housing low voltage cablesand the other for housing high voltage cables.
 6. A trough sectionaccording to claim 3, at least partially formed of reinforced concrete.7. A trough section according to claim 3, comprising a substantiallyunitary structure.
 8. A trough section according to claim 3, includingelectrical cables housed within the channels.
 9. (canceled)
 10. A railsystem according to claim 1, wherein the swept path is relativelyshallow.
 11. A rail system according to claim 1, wherein said ductingtrough is positioned generally centrally within said swept path.
 12. Arail system according to claim 1, wherein said ducting trough ispositioned at or adjacent the side of said swept path.
 13. A rail systemaccording to claim 1, further comprising a cantilevered structure forcarrying a feeder pole.
 14. A rail system according to claim 9, whereinsaid ducting trough comprises a combination of trough sections accordingto claim 7 and claim 8, respectively.
 15. A rail system according toclaim 14, wherein a trough section having a removable cover is placed atspaced-apart intervals along the length of the ducting trough.
 16. Amethod of providing a rail system, comprising the steps of providing anelongate ducting trough along a swept path, said ducting trough beingfor housing electrical cables, and providing at least one rail alongsideand generally parallel to said ducting trough.
 17. A method according toclaim 16, wherein said ducting trough and said at least one rail are insubstantially the same plane and/or at substantially the same level. 18.A method according to claim 17, wherein said ducting trough ispositioned substantially centrally within said swept path.
 19. A methodaccording to claim 17, wherein said ducting trough is positioned at oradjacent a side of said swept path.
 20. A rail system comprising aducting trough or a support member and at least one rail; the rail beingpositioned along side the ducting trough or support member.
 21. A railsystem according to claim 20, where the rail and ducting trough orsupport member are positioned at substantially the same depth.
 22. Arail system according to claim 21, wherein said rail and ducting troughor support members are of substantially the same height and/or insubstantially the same plane, in use.
 23. A trough or support sectionfor use in constructing a rail system, said trough or support sectionhaving securing means and defining at least one channel for housingelectrical and mechanical cables and equipment and being adapted to bepositioned generally along side at least one rail.
 24. A trough orsupport section according to claim 23, where the securing means is athread.
 25. A trough or support section according to claim 23, havingbuilt in radii at one or more ends such that two or more trough sectionsmay be positioned adjacent to each other and fit snugly together in boththe horizontal and vertical planes.
 26. A trough or support sectionaccording to claim 23 which is cast “in situ”.
 27. A trough or supportsection according to claim 23, defining at least two channels, one forhousing low voltage cables and the other for housing high voltagecables.
 28. A trough or support section according to claim 23, at leastpartially formed of reinforced concrete, composites, resin, or polymer.29. A trough or support section according to claim 23, comprising asubstantially unitary structure.
 30. A trough or support sectionaccording to claim 23, comprising a substantially solid structure.
 31. Atrough or support section according to claim 23, including electricalcables housed within the channels.
 32. A trough or support sectionaccording to claim 23, comprising at least one bar extending outwardfrom the section.
 33. A rail system according to claim 20, wherein saidducting trough or support member comprises one or more trough or supportsections according to claim
 19. 34. A rail system according to claim 33,comprising a depth of construction which is relatively shallow.
 35. Arail system according to claim 20, including means for carryingelectrical or mechanical equipment.
 36. A rail system according to claim35, wherein the carrying means is a cantilever structure.
 37. A railsystem according to claim 36, wherein said ducting trough or supportmember comprises a combination of trough or support sections.
 38. A railsystem according to claim 37, wherein said ducting trough or supportmember has one or more removable covers.
 39. A rail system according toclaim 38, wherein more than one removable covers are spaced apart atintervals along the length of the ducting trough or support member. 40.A method of constructing a rail system, comprising the steps ofproviding an elongated ducting trough or support member substantiallypositioned along side at least one rail.
 41. A method of constructing arail system according to claim 40, comprising the steps of laying anelongated ducting through or support member, then laying a sub-base,positioning at least one rail substantially along side the ductingtrough and then pouring a reinforced concrete slab.
 42. A method ofconstructing a rail system according to claim 40, where the at least onerail and ducting trough or support member are positioned atsubstantially the same depth.
 43. A method of constructing a rail systemaccording to claim 40, further comprising the additional step ofsecuring a gauge support frame to the ducting trough in order toposition the at least one rail.